Occam’s Razor is a frequently quoted principle which states that when one is faced with a multitude of seemingly complex possibilities, the simplest approach or explanation is best. As the ECB and Greece fight over terms of yet another bailout we employ this principle to help better grasp Greece’s dire situation.
The ratio of debt to GDP is one of the most basic and popular measures used to determine the ultimate ability of a sovereign nation to service its debt. Consider a country which has a debt to GDP ratio of 100%, and a balanced budget (excluding interest payments). In this country, it can be said that the interest rate on its debt and the growth rate of its GDP must be equal for the ratio to stay unchanged. In this example a 2% interest rate with a 1% GDP growth rate would result in an increase from 100% to 101% in the debt to GDP ratio.
As the ratio rises above 100%, the interest rate must be lower than the GDP growth rate or the ratio will continue to rise. At a debt to GDP ratio of 150%, a 2% interest rate would require a 3% growth rate to remain stable at 150%.
Greece has a current debt to GDP ratio of 170%, and based on current bailout terms, it will likely grow to well over 200%. So applying the logic from above, Greece’s GDP growth rate prior to the current bailout needed to be 1.70 times greater than the rate of interest Greece pays on its debt just to keep its ratio constant. Following are some facts which will allow us make judgments on Greece’s ability to improve or at least sustain its debt to GDP ratio: Since 1970 Greece’s best 5-year annualized GDP growth rate was +1.50% with an average of +.46%. Over the past 10 years growth has averaged -0.50%.
Since 1997 Greece’s lowest 5-year average interest rate on 10 year bonds was 3.41% with an average of 7.50%. Over the past 10 years the average annual 10 year interest rate was 8.16%
Read more: Michael Lebowitz Blog | The Simple Math Behind Greece’s Complicated Situation | Talkmarkets